Dirección de Estudios de Agua y Medio Ambiente, Área de Medio Ambiente Hídrico, Centro de Estudios Hidrográficos, CEDEX, Ministerio de Fomento, Paseo bajo de la Virgen del Puerto 3, 28005, Madrid, Spain.
Microb Ecol. 2011 Jul;62(1):162-76. doi: 10.1007/s00248-011-9853-4. Epub 2011 Apr 12.
A seasonal study of extracellular enzyme activities (EEA) was conducted in the coastal, sandy aquifer system located in the greater fluvial-littoral ecosystem of Doñana (SW, Spain). Glucosidase, leucine aminopeptidase, alkaline phosphatase, and phenol oxidase activities were determined over a 2-year period in 30 piezometers spread in an area of approximately 100 km(2). Taking into account all enzymes, piezometers, and seasons, EEA ranged over several orders of magnitude, from 1.01 × 10(-5) ± 2.92 × 10(-6) to 1.37 ± 0.13 nmol (methylumbelliferyl, amido-4-methylcoumarin, or dihydroxyphenylalanine) mL(-1) h(-1). The quality, much more than the quantity, of organic matter and nutrients seemed to be the major variables that controlled the spatiotemporal patterns showed by EEA. EEA patterns obtained in this study agree with several functional models of microbial communities, such as optimal resource allocation and nutrient co-limitation. This study probably represents the first one in which these functional models have been tested in subsurface systems. Results obtained in this study seem to suggest that microbial communities inhabiting groundwaters in Doñana are not dead or compromised cells. By contrast, these communities play relevant roles in carbon and nutrient cycling, continue with the decomposition process that begins in the sediments of the shallow lakes located in the area, provide remineralized carbon and nutrients to producers of these surface aquatic systems, and close energy and matter cycles. This study proposes that groundwater systems should be considered dynamic systems, comparable in functional complexity to surface systems.
本研究对西班牙多尼亚纳（Doñana）滨海沙质含水层系统（该系统位于较大的河流-滨海生态系统中）中的胞外酶活性（EEA）进行了季节性研究。在近 100 平方公里的区域内，利用 30 个测压计，在 2 年的时间内测定了葡萄糖苷酶、亮氨酸氨肽酶、碱性磷酸酶和酚氧化酶的活性。考虑到所有的酶、测压计和季节，EEA 的范围跨越了几个数量级，从 1.01×10(-5)±2.92×10(-6)到 1.37±0.13 nmol（甲基伞形酮、氨甲酰-4-甲基香豆素或二羟苯丙氨酸）mL(-1) h(-1)。有机物质和养分的质量，而不是数量，似乎是控制 EEA 时空分布模式的主要变量。本研究中获得的 EEA 模式与微生物群落的几种功能模型一致，如最佳资源分配和养分共限制。这可能是首次在地下系统中测试这些功能模型的研究之一。本研究的结果似乎表明，多尼亚纳地下水中的微生物群落并非是死亡或受损的细胞。相反，这些群落在碳和养分循环中发挥着重要作用，继续进行始于该地区浅湖底沉积物中的分解过程，为这些地表水生系统的生产者提供再矿化的碳和养分，并封闭能量和物质循环。本研究提出地下水系统应被视为具有与地表系统相当的功能复杂性的动态系统。
